1. Field of the Invention
Process and device for the inspection of glass
The invention relates to the field of automatic industrial inspection and more particularly concerns a process, and the corresponding device, for the inspection of glass.
2. Discussion of Background
In a general way, the purpose of the inspection of glass is the detection and the locating of defects, called "inclusions", which are generated in the course of the manufacturing phase in pieces of glass. The effect of these defects on the quality of the glass produced depends on their number, their shape and the standards imposed on the glassmakers according to the application aimed at. These defects are of two types:
"seed" type: the defects are gas bubbles which have remained captive within the material in the molten state; PA0 "stone" type: the defects are defects of homogeneity of the basic constituents involving the formation of a particle visible within the glass.
The size of these inclusions is in general less than 1 millimeter and the measuring thereof must be carried out with a high precision, at least for certain applications, the precision required possibly ranging from 1/10 to 1/100 of a millimeter.
The automatic detection of these defects is of great importance to glassmakers: a solution to this problem permits both an enhancement of the quality of the glass manufactured (improved compliance with the quality standards) and the availability of reliable statistics on the number and the size of the defects in order to modify, in consequence, the various production parameters of the glass.
The processes of inspection of glass which are currently known are restricted to the visual examination of the glass by a human observer. In fact, attempts to use artificial vision for the inspection of glass have not, up to the present time, given any results since these solutions effect a two-dimensional processing of the information. Accordingly, the corresponding processes do not permit the effective discrimination of the surface defects, dust and scratches, etc. . . . , which are eliminated by a single polishing of the glass, from the inclusions which are concealed in the mass of the glass.